In agile photonic networks, each signal travels between a different source and destination node without unnecessary OEO conversions at all intermediate nodes. In other words, the conventional pt-pt based channel boundaries are replaced by individual wavelengths (channels) going on-ramp and off-ramp at arbitrary network nodes.
Fault detection mechanisms which operate traditionally in the electrical domain cannot be applied in optical domain. Also, traditional network engineering methods cannot be used on end-to-end connections that pass through many nodes without OEO conversion, since the connections sharing a given fiber link now have substantially different noise and distortion impairments, determined by their network traversing history.
On the other hand, the agile architecture creates the opportunity to replace the existent fault detection mechanisms and the current methods of engineering connections with new link engineering methods.